Lehigh engineering professor is testing the usefulness of multitier networks in remote areas that lack digital and cable-modem access
When the providers of Internet services look at a map of Susquehanna County in northeastern Pennsylvania, they see a hilly, lightly populated region that offers little financial incentive to install the wires necessary for digital or cable-modem access.
When Shalinee Kishore looks at Susquehanna County, she sees a chance for wireless technology to give rural Americans the same access to modern telecommunications that urban and suburban residents enjoy.
And she feels privileged to tackle a problem that has implications for real people in the real world.
Kishore, assistant professor of electrical and computer engineering at Lehigh University, recently received a CAREER Award from the National Science Foundation to create multitier wireless networks and to demonstrate their usefulness in remote, under-served regions by developing an outreach program with Susquehanna County.
The five-year grant is one of the top national awards given to young professors in the U.S.
Multitier networks, says Kishore, can provide users in remote areas with the range of communication services people have come to expect, from high-speed Internet access at certain locations to lower-speed voice, data and messaging services everywhere.
The collaboration with Susquehanna County gives her a rare opportunity to put a "face on a research problem," Kishore says.
"As researchers, we very often work on theoretical problems. But theories need to be tested. This project allows us to test theories on a county with a distinct topography and distinct demographics.
"More than that, we get to solve problems that have interesting applications for real people. This project has enabled me to meet a lot of new people I didn't expect to meet."
Located along the eastern edge of Pennsylvania's long boundary with New York State, Susquehanna County contains 823 square miles, a population of 42,000 and a population density of 51 people per square mile. Only 30 percent of its residents live in the county's six largest towns.
Susquehanna County, which advertises itself as the gateway to Pennsylvania's "Endless Mountains," has a rugged terrain that is not hospitable to the laying of cable and wires. It does not have full cellular coverage or reliable 9-1-1 service. A satellite provides low-bit-rate coverage but at a high cost. One of the county's six high schools has wi-fi (wireless local area network) Internet access, but overall, the county lacks localized broadband access, and its wireless links are poor.
"Because of this lack of access, the county's residents feel they are being left behind the times," says Kishore, who was introduced to Susquehanna County the old-fashioned way - by friends and relatives who live there.
"They believe attracting Internet providers will help Susquehanna County achieve its goal of diversifying its economy and attracting more small businesses."
As part of her research project, Kishore will travel to Susquehanna County to conduct workshops and short courses for high school students, teachers, librarians and other residents on wireless technology and wireless possibilities. She will help residents develop and implement a plan to improve the county's wireless communications infrastructure and to adapt the technology to the peculiar needs of the county.
Kishore expects county residents to seek a wide range of applications for the new technology. The county's volunteer companies have told Kishore they would like to be able to communicate wirelessly with each other during emergencies. Hunters and farmers might want to investigate wi-fi GPS (Global Positioning System) capabilities. Students will likely want to install wi-fi Internet access at their high schools.
The other part of Kishore's project is to test and refine the multitier wireless networks that she believes are best suited to provide Susquehanna County with wireless communications and Internet access.
Multitier wireless technology, says Kishore, simultaneously provides ubiquitous low-rate coverage and targeted high-speed access through a network of base stations and user terminals, also called radios. The radios are designed with coverage areas that vary in their order of magnitude, Kishore says. "Higher-tier radios" extend the network's coverage area. "Lower-tier radios" target performance capabilities to specific locations.
One challenge for multitier wireless technology is to use as little bandwidth as possible. This is because the bandwidth allocated by the Federal Communications Commission is limited, requiring radios to utilize the same spectrum of bandwidth at the same time without interfering with each other.
Kishore's goal is to optimize scarce bandwidth and minimize interference caused by reuse of the bandwidth spectrum across tiers. Her approach, she says, represents "a novel and expansive study of spectrally efficient multitier architectures.
"In the past, multitier systems have been studied primarily in the cellular context and assuming little or no spectral reuse across tiers," she wrote in her proposal to the National Science Foundation.
"As the types of services required from wireless networks become increasingly varied, it is critical to develop a general and unified framework for multitier systems - one that includes varying degrees of spectral reuse between tiers and addresses not only cellular networks but also more ad-hoc [temporary] configurations."
Kishore will study both centralized systems in which users communicate with fixed access points, then non-centralized architectures in which control is distributed among radios and ad-hoc connections are possible.
To minimize interference caused by high spectral reuse, she will explore analytical methods that account for signal processing, radio resource allocation, and access control techniques.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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